Method and apparatus for producing a composite second image in the spatial context of a first image

Abstract: A method is disclosed for operating a processor-controlled machine to produce a composite view of an original, or first, image by combining the functions of multiple viewing operations and using the model data structure from which the first image was produced (called the "FIMDS".) A first viewing operation region (1VOR) (20) in a first viewing position in the display area (180) of the display device has displayed in the 1VOR (20) a second image produced according to a first viewing operation (VO1), associated with the 1VOR, that maps the FIMDS to image definition data defining the second image. Request signal data is received from a signal source to present a second viewing operation region (2VOR) (40) in the display area (180) coextensive with at least a portion of the 1VOR (20), forming a composite viewing operation region in the overlapping region. The 2VOR (40) has a second viewing operation (VO2) associated with it for mapping an input model data structure, typically but not necessarily the FIMDS, to image definition data defining a second image for display in the 2VOR (2VOR-SI), providing an alternate view of the FIMDS that is different from that provided by the VO1 associated with the 1VOR. In response to the request signal data, a composite viewing operation, composed from the functions of the VO1 and the VO2, maps the FIMDS to image definition data defining a composite image for display in the composite viewing operation region substantially at the same time as the first image is being displayed in the display area. This gives the perception to the machine user of applying composed viewing operations to information presented in the original image.

Description: The present invention relates generally to a method of operating a processor-controlled machine having a display for displaying images, and to a processor-controlled machine operated according to the method. More particularly, the present invention relates to producing a composite second image for display in the spatial context of a first displayed image by operating on the model data structure from which the first displayed image was produced, and using two or more displayed viewing operation regions for identifying the relevant portions of the image for which the composite second image is to be produced. A frequent and powerful use of a processor-controlled machine such as a computer is the presentation of information in the form of images on a display device connected to the machine. An image, which may include characters, words, and text as well as other display features such as graphics, is produced in a display area of the display device directly from an image definition data structure defining the image; the image definition data structure is typically stored in a memory area of the machine. One type of image format known as a raster image is composed of individual image locations commonly referred to as "pixels". The images discussed herein may be either static (having the appearance to a system operator or user of not moving), or animated, as, for example, in the case of a digital video image. An image definition data structure alone carries relatively limited data about the information content of the image the data represent. However, for many images, the image definition data structure is itself generated from another data structure which contains information or data capable of being understood by a human or by a software operation such as an application program which is executed by the machine's processor. Such a data structure will be referred to herein as the "information model data structure" or the "model data structure", and is to be distinguished from the image definition data structure. Examples of information model data structures include scene description models used by rendering operations to produce graphics images such as photorealistic scenes; and document models used by a word processing or other document manipulation application which contains the text, formatting instructions, and other data needed for producing a formatted document. In some systems providing user access to the model data structure, a user may be able to access, and perhaps affect or manipulate, data and information that is not represented by display features currently visible in the original image by producing, through alternate functions defined by the application, a second or alternate view of an original displayed image. The second view may provide enhanced information about the model data structure, or the system may then permit interaction with data in the model through the display features present in the second view. Typical of many of the systems implementing these types of multiple views of a model, the spatial relationship between the original image, the specification of the input content for the second image and the position of the second image in the display is not easy to visualize. While the specification of the input may be directly related to the first image (i.e. when the user can point to or select a region in the first image) this is not always the case as, for example, when the user has to type commands to specify a second image. Furthermore, once a selection is specified, the user either has no control over the location of the second image, or must reposition it in a separate step. Therefore, it can be difficult to understand how the second image is spatially related to the first image and to the model. Linking direct selection in the first image to the spatial position of the second image can make these relationships more clear. This can be especially important when the model is complex and can be viewed in many different ways. As systems supporting complex models, or sets of related models, are becoming more common, this problem is becoming more critical. Reference is made to a copending European patent application filed concurrently herewith and based on US-A-5 652 851. This application solves the problem of providing a second view of an original image in the spatial context of the original image by providing methods for operating a processor-controlled machine that operate on a model data structure from which a first image has been produced in order to produce a second image for display in the spatial context of the first image. A viewing operation region (VOR) is displayed coextensively with a first image segment of the first image in the display area of the machine's display device. The first image segment includes a display feature representing a model data item in the model data structure. In response to the display of the VOR, the method operates on the model data item in the model data structure to produce a second image for display in the VOR showing information related to the display feature in the original image. Multiple views of the same original image may be displayed by using more than one VOR positioned over different parts of the original image. A viewing operation associated with each VOR maps the model data structure that produced the original, or first, image, to the second image that provides the second view in the VOR. EPO 0 544 509, entitled "Photographic Filter Metaphor for Control of Digital Image Processing Software", discloses an example of the display of a composite second image in the spatial context of a first image. EPO 0 544 509 discloses a method and interactive user interface for displaying an image on a display device, selecting a filter for overlaying on a portion of the image, modifying for display the portion of the image overlaid by the filter while preserving the image as it appeared before modification, displaying the modified filtered portion of the image and retrieving the image as it appeared before the modification. Operations on the image pixel data structure alone, such as disclosed in EPO 0 544 509, provide versions and views of the first image which are limited strictly to manipulations of pixel values. So, while the software implementation of image processing filters provides some desirable features for generating the display of a composite alternate view of an original image, the range of information content possible in the second image which is derived directly from the image pixel data structure of the first image is necessarily limited to versions and views of the first image which result only from operating on the pixel values. For information available from the information model data structure of the first image, the methods used for operating on the image pixel data structure to produce image (pixel) magnification are not transferable. As a result, such methods are inoperable for general use in accessing alternative views of an information model data structure. One object of the present invention is to strive to provide a method of operating a machine which overcomes some of the disadvantages in the prior art above. Accordingly, the present invention provides a method, machine and article of manufacture in accordance with the appended claims. The present invention provides for composing, or combining, the functions of multiple viewing operations operating on a model data structure that produced an image in order to produce a single composite image displayed in the context of the original image. The composite image produced from composing the viewing operations may be an aesthetically enhanced image; or it may provide information from the first image model data structure displayed in a new manner or organization; or it may present new information from the first image model data structure not presented in the first image. The present invention is a method of operating a processor-controlled machine that includes a signal source for producing signals indicating image display requests, output circuitry connected to a display having a display area for presenting images, memory for storing data, and a processor connected for receiving the signals from the signal source, connected for providing data defining images to the output circuitry, and connected for accessing the data stored in the memory. The display area has a first image displayed in a present image position of the display area. The data stored in the memory of the processor-controlled machine include instruction data indicating instructions the processor executes, and a first image model data structure from which the first image was produced. Note that the term "first image" will be used herein interchangeably with the term "original image". For purposes of describing the invention and all of its embodiments in as concise a manner as possible, the following elements of the present invention will be referred to by their respective abbreviations. In the remainder of the specification a first viewing operation region will be referred to as 1VOR. A second image produced for display in the first viewing operation region will be referred to as 1VOR-SI. A first viewing operation will be referred to as VO1. A second viewing operation region will be referred to as 2VOR. A second image produced for display in the second viewing operation region will be referred to as 2VOR-SI. A second viewing operation will be referred to as VO2. A composite viewing operation region defined by the coextensively positioned portions of the first viewing operation region and the second viewing operation region in the display area will be referred to as C1 + 2VOR. A composite second image produced for display in the composite viewing operation region will be referred to as C1 + 2VOR-SI. The non-composite first viewing operation region, or the remaining portion of the first viewing operation region that is outside the composite viewing operation region will be referred to as 1VOR-NC. A second image produced for display in the non-composite portion of the first viewing operation region will be referred to as 1VOR-NC-SI. The non-composite second viewing operation region, or the remaining portion of the second viewing operation region that is outside the composite viewing operation region will be referred to as 2VOR-NC. A second image produced for display in the non-composite portion of the second viewing operation region will be referred to as 2VOR-NC-SI. In general, the terms n VOR and m VOR will be used to refer to multiple viewing operation regions, where n and m correspond to, respectively, the n th and m th viewing operation regions displayed. Finally, in general, for multiple viewing operation regions, C m + n VOR will be used to mean the composite viewing operation defined by the coextensively positioned portions of the m th viewing operation region and the n th viewing operation region in the display area. The method of the present invention begins with operating a processor to receive first request signed data from a signed source indicating a display request to present a first viewing operation region (1VOR) in a first viewing position in the display area of the display device, positioned coextensively with the present image position of a first image segment of a first image. The 1VOR has a first viewing operation (VO1) associated with it for modifying a first data item representing attributes of a first display feature of a first image, from which the first image was produced, to image definition data defining a second image for display in the 1VOR (1VOR-SI). The 1VOR-SI has size and shape dimensions substantially identical to size and shape dimensions of the 1VOR, and is presented in the 1VOR substantially at the same time as the first image is being displayed in the display area. The method of the present invention comprises a set of acts for producing an alternate view of the original image composed from the mappings of two viewing operations on the first image model data structure. Request signal data is received from the signal source indicating a display request to present a second viewing operation region (2VOR) in a second viewing position in the display area coextensive with the first viewing position of at least a portion of the 1VOR. The 2VOR has a second viewing operation (VO2) associated with it for mapping an input model data structure, typically the first image model data structure, to image definition data defining a second image for display in the 2VOR (2VOR-SI), the 2VOR-SI providing an alternate view of the first model data structure different from that provided by the VO1 associated with the 1VOR. Then, in response to the request signal data indicating the second display request, size and shape dimensions in the display area are determined for the portion of the 2VOR in the second viewing position coextensive with the first viewing position of the 1VOR, designated as a composite viewing operation region (C1 + 2VOR), using the first and second viewing positions of the 1VOR and the 2VOR, respectively. Then, a composite viewing operation is composed from the VO1 and the VO2, the composite viewing operation mapping the first image model data structure to image definition data defining a second image for display in the C1 + 2VOR (designated as a composite image, or C1 + 2VOR-SI) according to combined mappings of the VO1 and the VO2 on the first image model data structure. Next, the image definition data defining the C1 + 2VOR-SI is produced according to the composite viewing operation, using the size and shape dimensions of the C1 + 2VOR and the first image model data structure. The C1 + 2VOR-SI has substantially the same size and shape dimensions of the C1 + 2VOR. The image definition data defining the C1 + 2VOR-SI is then provided to the output circuitry connected to the display so that the display presents the C1 + 2VOR-SI in the C1 + 2VOR substantially at the same time as the first image is being displayed in the display area. The method of the present invention, when the composite second image (C1 + 2VOR-SI) is presented in the C1 + 2VOR, thus gives the perception to the machine user of showing the results of applying the composed viewing operations to information presented in the first image segment of the original first image. The present invention will be described further by way of examples with reference to the accompanying drawings, in which:- Figure 1 is a flow chart illustrating the acts of the method of operating a machine according to an embodiment of the present invention; Figure 2 illustrates a display screen showing the initial contents of the display area on which the method illustrated in Figure 1 operates; Figures 3, 4 and 5 illustrate a sequence of display screens showing a composite image produced according to the method illustrated in Figure 1; Figure 6 illustrates the portions of viewing operation regions defined by coextensively positioning two viewing operation regions; Figure 7 is a flow chart illustrating the acts of the method of the present invention for producing non-composite second images in the non-composite viewing operation regions illustrated in Figure 6; Figure 8 illustrates the three image planes of the display area implemented in the illustrated embodiment; Figure 9 illustrates the composite viewing operation region defined when the second viewing operation region completely overlaps the first viewing operation region; Figure 10 is a flow chart illustrating the acts of another implementation of the method of the illustrated embodiment; Figure 11 illustrates a display screen showing the first image and a second image produced according to a first viewing operation for a first viewing operation region; Figure 12 illustrates a display screen showing the first and second viewing operation regions, each having second images, produced according respective first and second viewing operations; Figure 13 illustrates a display screen showing the results of composing the first and second viewing operations illustrated in FIGS 11 and 12 according to the method illustrated in Figure 10; Figure 14 illustrates the composite second image displayed in the composite viewing operation region shown in Figure 13; Figure 15 is a block diagram illustrating the interaction between the systems components of an illustrated embodiment of the method of the present invention; Figure 16 is a portion of the block diagram in Figure 15 illustrating an alternative implementation for the systems components of the illustrated embodiment of the method of the present invention; Figure 17 is a block diagram illustrating the model-in, model-out implementation of producing a composite image according to the method of the present invention; and Figure 18 illustrates a processor controlled machine which the method of the present invention may operate. The terms defined below have the meanings indicated throughout this specification and in the claims. The term "data" refers herein to physical signals that indicate or include information. The term "data" includes data existing in any physical form, and includes data that are transitory or are being stored or transmitted. For example, data could exist as electromagnetic or other transmitted signals or as signals stored in electronic, magnetic, or other form. An "item of data" or a "data item" is a quantity of data that a processor can access or otherwise operate on as a unit. Data can be combined into a "data structure". A "data structure" is any combination of interrelated data. A data structure may also include other data structures. A "processor-controlled machine" or "processor" is any machine, component or system that can process data, and may include one or more central processing units or other processing components. A processor "uses" data in performing an operation when the result of the operation depends on the value of the data. An "instruction" is an item of data that a processor can use to determine its own operation. A processor "executes" a set of instructions when it uses the instructions to determine its operations. An item of data "indicates" a thing, an event, or a characteristic when the item has a value that depends on the existence or occurrence of the thing, event, or characteristic or on a measure of the thing, event, or characteristic. In addition, a first item of data "indicates" a second item of data when the second item of data can be obtained from the first item of data, when the second item of data can be accessible using the first item of data, when the second item of data can be obtained by decoding the first item of data, or when the first item of data can be an identifier of the second item of data. For example, when a first item of data indicates position information of an image display feature in the display area of a display device, and the position information may be used by the processor to obtain a second data item in a data structure, the first item of data indicates the second item of data. An "image" is a pattern of light. An image may include characters, words, and text as well as other features such as graphics. An image may be divided into image "segments," each of which is itself an image. A segment of an image may be of any size up to and including the whole image. An "image output device" is a device that can provide output defining an image. A "display" or "display device" is an image output device that provides information in a visible, human viewable form. A display may, for example, include a cathode ray tube; an array of light emitting, reflecting, or absorbing elements; a device or structure that presents marks on paper or another medium; or any other device or structure capable of defining an image in a visible form. To "present an image" on a display is to operate the display so that a viewer can perceive the image. A "display area" is the portion of the display in which an image is presented or the medium which receives an image. Data "defines" an image when the data includes sufficient information to directly produce the image, such as by presenting the image on a display. Data defining an image is referred to herein as an "image definition" or "image definition data". For example, a two-dimensional array is an image definition that can define all or any part of an image,typically called "image pixel data" or an "image pixel data structure", each item of data in the array providing a value, called a "pixel value", indicating the color of an image location. The term "display feature" refers to any human perception produced by a display in a processor-controlled machine or display system. A "display object" or "object" is a display feature that is perceptible as a coherent unity. A "shape" is a display object that has a distinguishable outline; for example, a circular display object is a shape. A shape having a bounded area may be called a "region". An image "includes" a display feature or object if presentation of the image can produce perception of the feature or object. Similarly, a display object "includes" a display feature if presentation of the display object can produce perception of the display feature. A "viewing operation region", also referred to herein as an "output producing region", is a region having an arbitrarily shaped, bounded area. A display feature "represents" a body of data when the display feature can be mapped to one or more items of data in the body of data, or, stated in another way, a display feature "represents" the item or items of data to which it can be mapped. For example, the display object perceived as a solid black line in an image may represent one or more items of data in the model data structure that an operation uses to produce the line's length, color and solidness. The mapping of one or more items of data to a display feature or object is performed by an "operation" which is used herein to mean a set of instructions (instruction data items) accessible and executable by the processor in a display system, defining the mapping relationship or function between one or more items of data (an input of the operation) and a display feature or object in an image (an output of the operation). An operation "produces" a display feature or object in an image when the operation begins without the data defining the display feature or object in the image and performing the operation results in the data defining the display feature or object in the image. The method of the present invention is a "model-based operation." A model-based operation uses "model data" as input to produce image definition data defining an image as output. A data item other than image definition data, for example, a data item other than an image pixel data item, is an "information model data item" or "model data". A model-based operation maps one or more model data items in a model data structure to a display feature included in the image produced by the operation. A combination of interrelated model data items is referred to herein as an "information model data structure", a "model data structure", or a "first image model data structure." For purposes of describing the invention herein, all model data items an operation uses to produce an image are considered to be included as part of the model data structure. Moreover, the model data structure is not limited to a combination of data items physically located in a substantially contiguous part of a system's memory, but may include individual model data items diversely located in memory and accessible by the processor when it performs the operation. In addition, the interaction between the model data and the operation, and the nature, quantity and'source of the data considered to be part of the model data structure, vary according to the functional capability of the model-based operation, which may itself vary considerably. The method of the present invention "operates on" an image when it uses the model data structure from which the image was produced to produce image definition data defining a second image. The model-based operation that produced the first, or original, image in the description of the invention that follows will be referred to as an "application". The model data structure may include data items that are not directly used by the application to produce the image but which may be known to and accessible by the application or another model-based operation. In addition, the model data structure may include a data item which, while used to produce the image, also indicates one or more other data items which are not used to produce the image and which are not included in the model data structure. For example, a data item in the model data structure represented by a display object in the image may also indicate a second model data item having characteristic or detail information about the display object that is not represented in the image. This second model data item may be included in the model data structure, or may be included in a different data structure linked to the model data structure. For example, in a model data structure that an application uses to produce a spreadsheet image, a data item having a value indicating a numerical entry in one of the columns may also indicate another data item containing the values indicating the individual numbers totaling the numerical entry in the spreadsheet, or the equation used by the spreadsheet cell to compute its numerical value. One type of model data structure from which an image can be produced according to the present invention may be composed of a collection of data items describing "objects". An "object" represents a semantic aspect of an application domain (e.g., letters, words, and paragraphs in a word processor; strokes in a drawing system; temporal events and dependencies in a project management system; etc.). Typically, an "object description data item" in the data structure is itself composed of other data items that describe a set of properties of the object. For a particular object, the properties may represent positional and visual attributes of the object that determine how the object will be perceived when displayed, in addition to application-specific attributes used by the application that produced the image. Typically also, each object, along with its properties, is uniquely addressable by a pointer or identifier, and thus objects can refer to each other in their descriptions. Objects or their properties may also describe relations or constraints between other objects. The term "display feature attribute data item" when used in reference to a data item in an object-based model data structure will refer to an object property. The present invention operates a variety of processor-controlled machines, each of which has the common components, characteristics, and configuration of machine 100 illustrated in FIG. 18. Machine 100 includes input circuitry 152 for receiving input "request" signals from one or more signal sources 154 indicating image display requests. Signal source 154 may include any signal producing source that produces signals of the type needed by the method of the present invention. Such sources include a variety of input devices controllable by a human user that produce signals generated by the user, and may also include other devices connected to machine 100 for providing such signals, including devices connected by wired or wireless communications facilities, such as through remote or local communications networks and infrared and radio connections. Signal source 154 may also include operations performed by machine 100, such as the operating system of a digital computer, or other applications performed by the digital computer. Signals from signal source 154 may include a "request" for an operation and information identifying the requested operation, wherein the signal or signals indicate one or more actions by a machine user intended to cause performance of the operation. An operation is performed by the machine "in response" to a request when the signals received are for indicating a valid request for a valid operation and for causing the operation to be performed. Signals indicating a single complete request may include a combination of any number of actions indicated by the user necessary for indicating a valid request for a valid operation and for causing the operation to be performed. Signal source 154, connected to input circuitry 152, may include, for example, a keyboard or a pointing device, used by the machine user to indicate actions. Suitable pointing devices include, but are not limited to, a mouse, a stylus or pen, and a trackball,or a user's finger making contact with a touch sensitive surface of display device 170. Processor 140 is connected for receiving the signals from input circuitry 152. Signals indicating user actions may include signals indicating the selection or movement of a display object visible to the user in display area 180, signals indicating requests that result in operations being performed by processor 140, and signals that result in processor 140 providing data defining an image to output circuitry 160 for display in display area 180. With continued reference to FIG. 18, machine 100 also includes memory 110 for storing data. Processor 140 is connected for accessing the data stored in memory 110, and for providing data for storing in memory 110. Memory 110 stores instruction data indicating instructions the processor executes, including the instruction data indicating the instructions for operating machine 100 according to the method of of the present invention. Processor 140 is also connected for providing data defining the first image 182 to output circuitry 160 for presentation on display device 170 in display area 180. The actual manner in which the physical hardware components of machine 100 is connected may vary, and may include hardwired physical connections between some or all of the components, connections over wired or wireless communications facilities, such as through remote or local communications networks and infrared and radio connections. The range of the physical size of either machine 100 may vary considerably from a machine that includes a very large display device 170 suitable, for example, for electronic whiteboard applications, to a machine that includes much smaller desktop, laptop, and pocket-sized or smaller display devices. The present invention operates machine 100 when display 170 has a first image 10 displayed in display area 180. The first image is produced using a first image model data structure 800 which is also stored in memory 110. There is further displayed in display area 180 a first viewing operation region 20 with a second image displayed therein. The initial contents of display area 180 are shown more clearly in FIG. 2. Note that abbreviations used in this description and in the figures are the same as those identified above. Image 10 comprises a simple black line having a thickness characteristic, or display feature, and having the display feature of being a solid line. Image 10 was produced using a first image model data structure stored in the memory 110 of the processor-controlled machine. A first viewing operation region 20 (1VOR) in a first viewing position in display area 180 is displayed coextensively with the present image position of a first image segment of first image 10. The first image segment includes a portion of the black line of image 10. 1VOR 20 has a first viewing operation (VO1) associated with it for providing a second image 24 for display in the 1VOR 20 (1VOR-SI) according to a mapping, or function, of an input model data structure, typically the first image model data structure, to the 1VOR-SI. Mappings, or functions, may be defined so as to produce a wide variety of second images including, but not limited to, a second image showing a modified display feature of a display feature in the first image segment; and a second image showing the results of a selection of a display object in the first image segment according to some criteria defined in the VO1 and matched to data in the first image model data structure. In the example illustrated in FIGS. 2 - 5, VO1 modifies the line thickness of lines in a first image. In the illustrated example, a new attribute value for the display feature attribute data item in the first image model data structure that determines the line thickness is obtained and used in place of the present attribute value so that the 1VOR-SI 24 includes the line having the modified line thickness. 1VOR-SI 24 has size and shape dimensions substantially identical to the size and shape dimension of 1VOR 20 and replaces the first image segment in the display area. Multiple views of the same original image may be displayed by using more than one VOR positioned over different parts of the original image. FIG. 3 illustrates a second viewing operation region (2VOR) 40 over a different portion of image 10. Note that 2VOR 40 has a different shape than 1VOR 20; in general, a viewing operation region is a display feature perceptible as a coherent unity having at least one distinguishable outline and at least one bounded area. The distinguishable outline defines and distinguishes the portion, or segment, of the first image for which a second image is produced from the remainder of the first image for which a second image is not produced. In the drawings, the exemplary viewing operation regions are illustrated as bounded areas with an explicitly drawn boundary line. However, the viewing operation region may have a topologically complex boundary, need not be a fixed or predetermined shape, and need not have an explicitly drawn border as long as it is perceptible as a coherent, distinguishable bounded area. 2VOR 40 has a second viewing operation (VO2) associated with it for providing a second image for display in the 2VOR 40 (2VOR-SI) according to a mapping, or function, of an input model data structure, also typically the first image model data structure, to the 2VOR-SI. As with VO1, VO2 may map its input model data structure to one of a wide variety of possible second images. FIG. 3 shows the VO2's mapping of the first image model data structure to the 2VOR-SI when the 2VOR is positioned coextensively with a second image segment of the first image. VO2 changes the "solid" display feature of the black line to that of "broken" to produce a broken black line. Figure 1 illustrates the acts of method 200 of the present invention operating on image 10 to produce a composite second image. Display screens 180 in FIGS. 4 - 5 illustrate the features of the method. A request to display a second viewing operation region 40 (2VOR) in a second viewing position in display area 180 coextensive with the present image position of a second image segment of first image 10 is received, in box 220. The second image segment also includes a portion of the black line of image 10. The request signal received in box 220 may be a user request signal indicating a movement action on the display of the 2VOR 40 from a first position to the second viewing position in display area 180 coextensive with the present image position of a second image segment of first image 10. FIG. 4 shows in dotted lines the user-directed "movement" of 2VOR 40 along path 42 to a position in display area 180 coextensive with at least a portion of the first viewing position of 1VOR 20. In response to the request to display 2VOR 40, method 200 causes processor 140 to perform the component acts shown in box 230. First, the size and shape dimensions of the portion of 2VOR 40 that is positioned in display area 180 coextensively with the first viewing position of 1VOR 20 are determined, in box 232, using the viewing positions of each respective viewing operation region. This overlapping region, shown more clearly in FIG. 6, will be called hereafter the composite viewing operation region 60, or C1 + 2VOR 60. These size and shape dimensions are generally determined through simple manipulation of the geometric outlines of the regions. Next, in box 246, image definition data defining a composite second image (C1 + 2VOR-SI) for display in C1 + 2VOR 60 is produced using the size and shape dimensions of C1 + 2VOR 60, and according to a composite viewing operation that maps the first image model data structure to the image definition data defining the composite image. The composite second image has the size and shape dimensions of C1 + 2VOR 60. The composite viewing operation is produced by combining the mapping or function defined by the VO1 on its input model data structure with the mapping or function defined by the VO2 on its input model data structure. In the illustrated example, both viewing operation mappings recognize the first image model data structure as a valid input model data structure. However, regardless of the specific manner in which the functions are combined, in order to produce a composite image that makes intuitive sense to a machine user of the method, a viewing operation ordering rule must be adopted and adhered to consistently for each composite image produced. That is, whether the mapping of VO1 is performed on the first image model data structure before the mapping of VO2 is performed on its respective input model data structure, or vice versa, must be determined and applied consistently for all composite viewing operations. The viewing operation ordering rule adopted in the illustrated embodiment is related to the two-and-one-half dimensional ("2.5D") appearance of display area 180, illustrated in FIG. 8, showing display area 180 from the perspective of human user 181 having three image planes 189, 190 and 192.. First image 10, 1VOR 20, and 2VOR 40 have the appearance in display area 180 of each being in a different image plane, creating the appearance of a 2.5D image display area 180. Image plane 189 shows first image 10, while image planes 190 and 192 show 1VOR 20 and 2VOR 40 respectively. In the illustrated graphical user interface implementation, in which the user directs the movement of 1VOR 20 and 2VOR 40, the user may move first image 10 in image plane 189 "under" 1VOR 20 in image plane 190, or may move 1VOR 20 in image plane 190 "over" a portion of first image 10 in image plane 189. Similarly, the user may move 1VOR 20 image plane 190 "under" 2VOR 40 in image plane 192, or may move 2VOR 40 in image plane 192 "over" 1VOR 20 in image plane 190. Since each image position 183 in image plane 189 corresponds to an image position 185 in image plane 190 and to an image position 187 in image plane 192, as a result of the user's interaction, 2VOR 40 may be positioned coextensively with a portion of 1VOR 20 and with an image segment of first image 10. The image planes create the appearance of an overlapping order. In the illustrated embodiment, the composite viewing operation is implemented by combining the VO1 and the VO2 in the overlapping order of their respective viewing operation regions in display area 180, beginning with the viewing operation associated with the viewing operation region closest to the image plane containing first image 10. Then, in box 258, the image definition data defining the composite second image is provided to the output circuitry connected to display 170 so that display 170 presents the composite second image in the C1 + 2VOR in display area 180 substantially at the same time as the first image is being displayed in display area 180. FIG. 5 illustrates composite image 50 in C1 + 2VOR 60. VO1, which changes the thickness of the line in image 10 to a thicker line, is combined with VO2, which changes solid lines to broken lines, are combined to produce a broken, thicker line in composite image 50, thus giving the perception to the machine user of showing the results of applying the composite viewing operation to information presented in the first image segment. It can also be seen from FIGS. 5 and 6 that, in addition to C1 + 2VOR 60, other viewing operation regions are created when 1VOR 20 is positioned coextensively with 2VOR 40. The method of the present invention recognizes that a machine user will derive additional benefit from the method when the second images defined by the individual mappings, VO1 and VO2, of the first image model data structures are also produced and displayed in display area 180 in these other regions. In FIG. 6, it can be seen that the portion 28 of 1VOR 20 not positioned coextensively with 2VOR 40, designated as the non-composite portion of 1VOR, or 1VOR-NC 28, is available for showing a portion of 1VOR-SI 24 produced according to VO1, as shown in FIG. 2. Similarly, a portion 48 of 2VOR 40, not positioned coextensively with 1VOR 20 and designated as the non-composite portion of 2VOR, or 2VOR-NC 48, is available for showing a portion of 2VOR-SI 44 produced according to VO2, as shown in FIG. 3. In effect, each of the different regions may be treated as separate viewing operation regions, each with an associated viewing operation. FIG. 7 illustrates additional component acts of the method for producing these additional images in response to receiving the display request signal in box 220. The size and shape dimensions of 1VOR-NC 28 and of 2VOR-NC 48 are determined, in boxes 236 and 240, using the first and second viewing positions of the respective 1VOR 20 and 2VOR 40. Then, in box 250, image definition data defining a second image for display in the 1VOR-NC 28 (1VOR-NC-SI) is produced according to the mapping defined by the VO1 using the first image model data structure and the size and shape dimensions of the 1VOR-NC 28. Next, in box 254, image definition data defining a second image for display in the 2VOR-NC 48 (2VOR-NC-SI) is produced according to the mapping defined by the VO2 using the first image model data structure and the size and shape dimensions of the 2VOR-NC 48. Finally, the image definition data defining the second images for the 1VOR-NC 28, the 2VOR-NC 48, and the C1 + 2VOR 60 are provided to the output circuitry connected to the display so that the display presents the 1VOR-NC-SI in the 1VOR-NC 28, presents the 2VOR-NC-SI in the 2VOR-NC 48, and presents the composite second image in the C1 + 2VOR substantially at the same time as the first image is being displayed in the display area. FIG. 5 shows the results of these acts. 1VOR-NC-SI 26 in 1VOR-NC 28 shows the black line of image 10 having increased thickness with the original solid line display feature, while 2VOR-NC-SI 46 in 2VOR-NC 48 shows the black line of image 10 as being a broken line of the original line thickness. Presentation of the 1VOR-NC-SI, the 2VOR-NC-SI, and the composite second image substantially simultaneously thus gives the perception to the machine user of providing multiple views of the first image related to information in the respective image segments coextensive with the viewing positions of the 1VOR-NC, C1 + 2VOR and 2VOR-NC in the display area. It is also possible for the different viewing operation regions to so substantially overlap as to eliminate either 1VOR-NC 28 or 2VOR-NC 48, or both. FIG. 9 illustrates the case where there is no, or substantially no, non-composite viewing operation region for 1VOR 20, and where composite image 50 in C1 + 2VOR 62 replaces all of the 1VOR-SI in 1VOR 20. A specific implementation of composing viewing operations involves producing a second model data structure as the output of a viewing operation that is first in the order of composition using the first image model data structure, and then providing that second model data structure as the input to the viewing operation second, or next, in the order of composition. The second model data structure contains the necessary data items from which the second image for the first viewing operation is produced. Thus, applying the second viewing operation to the output data structure of the first viewing operation has the effect of composing the viewing operations and applying the composite operation on the first image model data structure. FIG. 10 illustrates the acts involved in this "model-in model-out" implementation, denoted as method 300. FIGS. 11, 12, and 13 illustrate a series of display screens showing the operation of method 300. 1VOR 20 has a first viewing operation (VO1) associated with it for providing a second image 24 for display in the 1VOR 20 (1VOR-SI) according to a mapping of the first image model data structure to the 1VOR-SI. VO1 is the same viewing operation described earlier, that of changing the thickness of lines in an image. In response to the first display request signal, the component acts in box 310 are performed. A second model data structure is produced, in box 312, according to the VO1 and using the first image model data structure. In the example shown, the first image model data structure, including the display feature data items represented by the lines and the thickness of the lines in image 12, is copied to a second model and the appropriate copied display feature data items are changed to have the new value of an increased thickness. Then, in boxes 316 and 318, image definition data defining the 1VOR-SI 24 is produced from the second model data structure and displayed in 1VOR 20, as shown in FIG. 11. A second viewing operation region, 2VOR 70 also has a viewing operation (VO2) associated with it for providing a second image for display in the 2VOR 70 (2VOR-SI) according to a mapping of the first image model data structure to the 2VOR-SI. FIG. 12 illustrates the 2VOR-SI in 2VOR 20. The VO2 changes the color of triangular objects in the image to blue, designated by the fill-in pattern shown in FIG. 12 in the portion 74 of the triangle in image 12 that is within the boundary of 2VOR 70. Producing the composite image is illustrated in boxes 220 and 340, and shown in FIG. 13. A second request signal is received, in box 220, to display 2VOR 70 in a second viewing position in display area 180 coextensively with a portion of the first viewing position of 1VOR 20. In response to the second display request, method 300 causes processor 140 to perform the component acts shown in box 340. First, the size and shape dimensions of the composite viewing operation region 72, or C1 + 2VOR 72 are determined, in box 232, using the first and second viewing positions of each respective viewing operation region. Next, in box 354, image definition data defining the composite second image for display in C1 +2VOR 72 is produced according to the VO2 using the second model data structure as input to VO2, and using the size and shape dimensions of C1 + 2VOR 72. In the illustrated example, the VO2 operates on the second model which has data items represented by thicker line segments in 1VOR-SI, and accesses the triangle object data item and its fill-color attribute data item in order to perform the VO2. The resulting composite second image has the size and shape dimensions of C1 + 2VOR 72. Then, in box 258, the image definition data defining the composite second image is provided to the output circuitry connected to display 170 so that display 170 presents the composite second image in the C1 + 2VOR 72 in display area 180 substantially at the same time as the first image is being displayed in display area 180. The non-composite images for the first and second non-composite viewing operation regions are produced in the same manner as described above in the discussion accompanying the flow chart of FIG. 7. One embodiment of the method of the present invention has been implemented as a set of interactive user-controlled functions, or viewing operations, added to the functionality of a graphical object editor application software program which operates in a graphical user interface system environment. Each viewing operation in the implemented embodiment operates on the object-based model data structure of the graphical objects editor, hereafter called the graphical editor data structure, which has structural features similar to model data structure 860 described earlier. It is important to note that the method of the present invention may be implemented to operate in any of the variety of graphical user interfaces currently available for computer workstations and other types of machines having processors and displays, including personal computers, fully-featured copier-duplicators, production publishing machines, and image reproduction machines. Further, while the implemented embodiment operates on the object-based model data structure of a graphical objects editor, it is intended that the method may be implemented to operate in a wide variety of application environments. The illustrated embodiment has been implemented on a Sun Microsystems SPARCstation 10 computer as a research software prototype application written in the Cedar programming environment, a Xerox proprietary research software environment, utilizing the Cedar programming language, and running on the SunOS UNIX® -compatible operating system. The Cedar programming environment provides application support for a graphical user interface environment including software functions both for presenting and managing images for display in plural workspaces or "windows" in the display area of the display, and for interfacing with at least one pointing device, to be manipulated by a user of the machine. The user uses the pointing device to communicate operational commands to the graphical user interface, and, through the interface, to each software application operating in each window. The illustrated implementation also operates within the framework of an editing environment known as MMM (Multi-Device Multi-User Multi-Editor. MMM operates as a single window in the Cedar programming environment, and allows for multiple applications, including the graphics editor application, to execute as subwindows within the MMM window. MMM takes events from multiple input devices, such as a mouse and a trackball, keeps track of which device produced which event, and places all events on a single queue. It dequeues each event in order and determines to which application that event should be delivered. MMM applications are arranged in a hierarchy that indicates how they are nested on the screen. Each event is passed to the root application, which may pass the event on to one of its child applications, which may in turn pass the event on down the tree. Mouse events are generally delivered to the most deeply nested application whose screen region contains the mouse coordinates. However, when the user is dragging or resizing an object in a particular application, all mouse coordinates go to that application until the dragging or resizing is completed. Keyboard events go to the currently selected application. Additional information about the MMM environment may be found in Eric A. Bier and Steve Freeman, "MMM: A User Interface Architecture for Shared Editors on a Single Screen" in the Proceedings of the ACM SIGGRAPH Symposium on User Interface Software and Technology (Hilton Head, SC, Nov. 11-13, 1991), ACM, New York, 1991, at pp 79-86. The underlying structure of the Cedar environment, designated collectively as reference numeral 118 in FIG.15, is a collection of components that are arranged in hierarchical layers, supporting a well integrated, interactive environment in which lower level modules remain directly available to higher level, or "client" programs, callable as ordinary Cedar language procedures. In addition, a higher level Cedar component can supply a procedure value as a parameter to a lower level service procedure, which in turn can later invoke the higher level component to communicate with it as necessary. Cedar environment 118 controls different application contexts controlled by processor 140 by separating them physically into different parts of one or more display screens. Application programs, such as the Gargoyle graphics editor 120, in the Cedar programming environment are called "clients" of the environment. The Cedar environment includes a high-level software window management system 112, hereafter called "window manager 112", which provides the necessary window management control for the application client programs that execute on the machine. Viewing operation software 200 contains the software instructions for defining and implementing a viewing operation according to the method of the present invention and for interacting with the graphical editor data structure used by Gargoyle graphics editor 120 in order to produce the second image. Viewing operation 200 has been implemented to cooperate with the functionality of the Gargoyle graphics editor 120, and is a client of window manager 112. Each application client 200 and 120 exchanges data with user interaction device 154 and display 170, via window manager 112 by converting signals received from inout circuitry 154 into a series of user input signals for directing control of processor 140 (FIG. 18) to perform the operations of Gargoyle graphics editor 120 and to perform viewing operation 400, including creating and drawing the viewing operation region 186 in the Gargoyle graphics editor window 211, on display 170, in response to request signals from the user. In the illustrated embodiment, method 400 is implemented as a separate application, and the MMM editor handles any interaction between application 120 and method 400. However, as shown in FIG. 16 ., the method of the present invention may also be implemented as a functional enhancement to application 120 which interacts with window management system 112 in graphical user interface environment 118, designated as collective entity 122. In this implementation, the method of the present invention takes advantage of the graphics editor application software in the memory of the machine, and utilizes relevant portions of the application code to perform the viewing operation on the appropriate model data structure and to produce the image definition data defining the output (second or composite) image. The method and its variations illustrated above and encompassed by the appended claims may be expanded to apply to more than two viewing operation regions, and may be straightforwardly expanded to include producing composite and non-composite images for each of the newly added regions that are defined by adding new viewing operation regions. In the "model-in model-out" implementations it is possible to have a viewing operation associated with a first viewing operation region that does not operate on the same model data structure as its input model data structure as another viewing operation associated with a second viewing operation region, such that the output model of the first viewing operation is not recognized or understood as a valid input model for the second viewing operation. The second viewing operation may be implemented to handle this in a manner suitable for the particular application. For example, the second viewing operation may simply not operate on the unknown input model, leaving, or passing, it unchanged, and may present the same second image in the composite viewing operation region that was presented by the VO1 in that portion of the 1VOR Or, the second viewing operation may have the ability to convert the input model to the model type that it is capable of operating on. One example of the latter capability arises when a viewing operation operates on a standard graphics or page description language, such as PostScript or interpress. When the method of the present invention is implemented as a set of features integrated with an application program, the application may be instructed to convert its model to the page description language model for input to a viewing operation whenever a viewing operation region requiring a page description language model is positioned over the image produced by the application program. The viewing operations in a model-in, model-out implementation of the method of the present invention may be regarded as model conversion operations, converting an input model data structure to an output model data structure, which in turn becomes the input model to suosequent viewing operations This is the intention expressed in method 300 shown in the flowchart of FIG. 10. In some cases, the output model may simply be a copy of the input model, or the output model may be a model that functions as a copy of the input model, but is not an entire copy; in other cases the output model will be a different type of output model altogether In this manner, processing rules may be established for carrying out the proper ordering of the viewing operations on their respective input models for composing viewing operations, and for handling incompatibilities between input model and viewing operation. FIG. 17 illustrates this processing pipeline for three viewing operations for associated overlapping viewing operation regions. Each of the viewing operations produces image definition data defining an image for its respective viewing operation region boundary, and produces an output model; image definition data defining the composite image 54 for the composite viewing operation region 52 is determined from applying each viewing operation to its respective input model and using size and shape information about the composite viewing operation region 52. A viewing operation does not necessarily clip its output model during its conversion from the input to the output model; an optimized implementation might make use of the region boundaries to convert only a part of the model, but a preferred implementation produces at least as much of the output model as is needed to fill its associated viewing operation region. It thus may become important in the implementation of the method chosen for determining how much of the input model is needed to convert to the output model to take into account the function of the viewing operation associated with each viewing operation region positioned "above" or "on top of" lower-level viewing operation regions when composing images. Thus, in general, the input model region of a group of composed (or coextensively positioned) VORs taken as a whole can be determined by applying the inverse of each respective viewing operation in the group to each respective VOR boundary.

Claims: A method of operating a machine; the machine including: a signal source for producing signals indicating image display requests; a display having a display area for presenting images; the display area having a first image displayed in a present image position therein; the first image including a first display feature, a processor connected for receiving the signals from the signal source, and connected for providing images to the display; and memory for storing data; the data stored in the memory including: instruction data indicating instructions the processor executes; and a first image model data structure including a first data item representing attributes of the first display feature; the first image being produced from the first image model data structure; the processor further being connected for accessing the data stored in the memory; the method including: operating (302) the processor to receive first request signal data from the signal source indicating a display request to present a first viewing operation region in a first viewing position coextensive with the present image position of a first image segment of the first image; the first viewing operation region having a first viewing operation associated therewith for modifying the first data item to define a second image for display in the first viewing operation region; operating (220) the processor to receive second request signal data from the signal source indicating a display request to present a second viewing operation region in a second viewing position in the display area coextensive with the first viewing position of at least a portion of the first viewing operation region; the second viewing operation region having a second viewing operation associated therewith for modifying the first data item to define a second image for display in the second viewing operation region; and operating the processor to respond to the second request signal data by: determining (232) size and shape dimensions of the portion of the second viewing operation region in the second viewing position coextensive with the first viewing position of the first viewing operation region, designated as a composite viewing operation region, in the display area using the first and second viewing positions of the first viewing operation region and the second viewing operation region, respectively; producing (354) composite image definition data defining a composite image for display in the composite viewing operation region according to a composite viewing operation and using the size and shape dimensions of the composite viewing operation region; the composite viewing operation modifying the first data item to define the composite image according to combined modifications of the first data item by the first viewing operation and the input data item by the second viewing operation; the composite image having the size and shape dimensions of the composite viewing operation region; and presenting (258) the composite image in the composite viewing operation region substantially at the same time as the first image is being displayed in the display area; whereby presentation of the composite image in the composite viewing operation region gives the perception to the machine user of showing the results of applying the composite viewing operation to information presented in the first image segment. A method as claimed in claim 1 wherein the act of operating the processor to respond to the second request signal data further includes: determining (236) size and shape dimensions of a remaining portion of the first viewing operation region in the first viewing position outside the second viewing position of the second viewing operation region, designated as a non-composite first viewing operation region, in the display area using the first and second viewing positions of the first viewing operation region and the second viewing operation region, respectively; producing (250) image definition data defining a second image for display in the non-composite first viewing operation region according to the modification defined by the first viewing operation using the first image model data structure and the size and shape dimensions of the non-composite first viewing operation region; determining (240) size and shape dimensions of a remaining portion of the second viewing operation region in the second viewing position outside the second viewing operation region, designated as a non-composite second viewing operation region in the display area using the first and second viewing positions of the first viewing operation region and the second viewing operation region, respectively; producing (254) second image definition data defining a second image for display in the non-composite second viewing operation region according to the modification defined by the second viewing operation using the first image model data structure as the input model data structure and the size and shape dimensions of the non-composite second viewing operation region; and presenting (258) the second image for display in the non-composite first viewing operation region and presenting the second image for display in the non-composite second viewing operation region in the display area substantially at the same time as the composite image is being displayed in the composite viewing operation region and the first image is being displayed in the display area; whereby presentation of the second image for display in the non-composite first viewing operation region, the second image for display in the non-composite second viewing operation region, and the composite image substantially simultaneously gives the perception to the machine user of providing multiple views of the first image related to information in respective first image segments coextensive with viewing positions of the non-composite first viewing operation region, composite viewing operation region and non-composite second viewing operation region in the display area. A method as claimed in claim 1 or claim 2, wherein the composite image according to the composite viewing operation includes: producing (312) a second model data structure according to the modification defined by the first viewing operation using the first image model data structure; and producing (354) the composite image definition data defining the composite image according to the modification defined by the second viewing operation using the second model data structure as the input model data structure. The method as claimed in any one of claims 1 to 3, wherein: the first image, the first viewing operation region, and the second viewing operation region are arranged in the display area so as to have the appearance of being in different image planes; the first image having the appearance of being displayed in a first image plane; the first viewing operation region having the appearance of being displayed in a second image plane, in front of the first image plane; the second viewing operation region having the appearance of being displayed in a third image plane, in front of the second image plane; the first viewing operation region and the second viewing operation region arranged so as to have an overlapping order in the display area with respect to an image plane closest to the first image plane; and the act of producing the image definition data defining a composite image for display in the composite viewing operation region according to a composite viewing operation includes combining the first viewing operation and the second viewing operation according to the overlapping order of the first viewing operation region and the second viewing operation region in the display area, beginning with the first viewing operation associated with the first viewing operation region in the image plane ordered closest to the first image plane. A method according to claim 2, wherein: the first image includes a first display object having a present object position in the first image; the first image model data structure comprises an object-based model data structure including a first object data item represented by the first display object, and an object coordinate data item indicating display object coordinate information about the present object position of the first display object, the object coordinate data item indicating the first object data item; and the act of producing first image definition data includes the step of producing an object-based second model data structure using the first object data item; the second model data structure including an output object coordinate data item indicating output display object in the second image for display in the first viewing operation region; the output object coordinate data item indicating the output object data item. A method according to claim 1, wherein the first image includes a first display object having the first display feature; the first image model data structure includes a first object data item represented by the first display object in the first image; the first object data item indicating a display feature attribute data item having a present attribute value indicating the first display feature when displayed in the display area; and the instruction data includes first image application instruction data defining an application operation capable of producing the first image from the first image model data structure; and further comprising the step of operating the processor to respond to the first request signal data indicating the display request by performing the acts of: obtaining a first new attribute value for the display feature attribute data item; the first new attribute value indicating a modified first display feature; copying the first image model data structure to a copied first image model data structure; the copied first image model data structure including a copied first object data item indicating a copied display feature attribute data item having the present attribute value indicating the first display feature; obtaining the copied first object data item and the copied display feature attribute data item from the copied first image model data structure; replacing the present attribute value of the copied display feature attribute data item with the first new attribute value in the copied first image model data structure; obtaining second image size-and-position data from the first viewing position of the first viewing operation region in the display area; the second image sizeand-position data indicating size and position information about a second image for display in the first viewing operation region; executing the first image application instruction data defining the application operation to produce image definition data defining the second image for display in the first viewing operation region using the second image size-and-position data and the copied first image model data structure including the first new attribute value for the copied display feature attribute data item; the second image for display in the first viewing operation region including the first display object having a once-modified first display feature; the second image for display in the first viewing operation region having size and shape dimensions substantially identical to size and shape dimensions of the first viewing operation region; and providing the image definition data defining the second image for display in the first viewing operation region to the display so that the display presents the second image for display in the first viewing operation region in the first viewing operation region; the second image for display in the first viewing operation region being displayed substantially at the same time as the first image is being displayed in the display area; and the step of operating the processor to respond to the second request signal data further comprises the acts of: obtaining a second new attribute value for the copied display feature attribute data item; the second new attribute value indicating a twice-modified first display feature; obtaining the copied first object data item and the copied display feature attribute data item from the copied first image model data structure using the size and shape dimension data; and replacing the first new attribute value of the copied display feature attribute data item with the second new attribute value in the copied first image model data structure; and wherein the act of producing composite image definition data includes the step of executing the first image application instruction data defining the application operation to produce image definition data defining a second image for display in the composite viewing operation region using the size and shape dimension data of the composite viewing operation region and the copied first image model data structure including the second new attribute value for the copied display feature attribute data item; the second image for display in the composite viewing operation region, designated as a composite image, including the first display object having the twice-modified first display feature and having size and shape dimensions substantially identical to size and shape dimensions of the composite viewing operation region. A machine for carrying out the method of any of claims 1 to 6, the machine including: input circuitry connected to a user input device; the input circuitry receiving signals indicating requests of a machine user; output circuitry connected to a display having a display area for presenting images; the display area having a first image displayed in a present image position therein; the first image including a first display feature; a processor connected for receiving the signals from the input circuitry, and connected for providing image definition data defining images to the output circuitry for presentation by the display; and memory for storing data; the data stored in the memory including: instruction data indicating instructions the processor can execute; and a first image model data structure including a first data item representing attributes of the first display feature; the first image being produced from the first image model data structure; the processor being further connected for accessing the data stored in the memory. A machine according to claim 7 further including: a storage medium access device for accessing a medium that stores data; and wherein the processor further being connected for receiving data from the storage medium access device. A machine according to claim 8 further including an article of manufacture, said article of manufacture comprising: a data storage medium that can be accessed by the storage medium access device when the article is used in the machine; and data stored in the data storage medium so that the storage medium access device can provide the stored data to the processor when the article is used in the machine; the stored data comprising instruction data indicating instructions the processor can execute.

Inventors: BIER ERIC A, DEROSE ANTHONY, FISHKIN KENNETH P, STONE MAUREEN C, BIER, ERIC A., DEROSE, ANTHONY, FISHKIN, KENNETH, P., STONE, MAUREEN C.
Applicants: XEROX CORP, XEROX CORPORATION
Application year: 1994
Main classification: G06F9
IPC codes: G09G5, G06T11, G06F17